In article <clcm-20080217-0014@[EMAIL PROTECTED]
>, Chris LaVelle
<cjlavelle@[EMAIL PROTECTED]
> wrote:
> I don't know the easiest way to explain this so, I'm going to give an
> example of how it is today....and what I'm trying to accomplish.
> [snip pseudo code for var array size in struct]
> Ok, let's just say element is bigger than my example above and there are
> about a 1000 of these, only half of which have data. I've inherited
> this code and this table is occupying 300k of memory and memory's tight.
> I want to delete all the filler rows and declare element in a way that
> the compiler will auto size what it needs for each instance. I have the
> number of elements. I would have thought something along the lines of
> *element instead of element[MAX_E]. But I get warnings about the
> unexpected brace for element. Is there a way to make the compiler auto
> size the space for me? In the above example I would be deleting rows
2-8.
>
Well you can name each arrray within the array and instead of an
array of ELEMENT_T have an ELEMENT_T * in the outer struct.
Safer is to have an extern T_table[]; in the header and a separate
file with static ELEMENT_T []'s like this
/* table.h */
#include <stdint.h>
typedef struct table_data
{
uint8_t num;
uint8_t param;
uint16_t fre1;
int16_t a1;
} table_data;
typedef struct table_entry
{
uint8_t num_elements;
uint8_t flag;
table_data *elements;
} table_entry;
extern table_entry table[];
/* end table.h */
/* table .c */
#include "table.h"
#define RUN_0_SIZE 2
static table_data run_0[RUN_0_SIZE] =
{
}2.0,480,-240},
{0,0,0,500}
};
#define RUN_1_SIZE 3
static table_data run_1[RUN_1_SIZE] =
{
{2,3,4,6},
{3,4,7,8},
{5,5,6,9}
};
/* etc */
table_entry table [] =
{
{RUN_0_SIZE,3,run_0},
{RUN_1_SIZE,4,run_1},
/* etc */
};
/* end file */
This costs an additional pointer per entry in table, over min.
memory allocation for the data but is automatic if the data
is separated this way. You might want a short program to
rearrange the data in this form to be sure the size of the
array in a table entry is at least the number of entries in the
corresponding array that elements points to.
I think this is standard c99 not sure, as I ussually code in c++.
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